Electronic device including touch-sensitive display

ABSTRACT

A method includes detecting a touch on a touch-sensitive display, determining a time of a display update of the touch-sensitive display, and adjusting a scanning rate of scanning electrodes of the touch-sensitive display based on the time of the display update.

FIELD OF TECHNOLOGY

The present disclosure relates to electronic devices including, but notlimited to, portable electronic devices having touch-sensitive displaysand their control.

BACKGROUND

Electronic devices, including portable electronic devices, have gainedwidespread use and may provide a variety of functions including, forexample, telephonic, electronic messaging and other personal informationmanager (PIM) application functions. Portable electronic devices includeseveral types of devices including mobile stations such as simplecellular telephones, smart telephones (smart phones), Personal DigitalAssistants (PDAs), tablet computers, and laptop computers, with wirelessnetwork communications or near-field communications connectivity such asBluetooth® capabilities.

Portable electronic devices such as PDAs, or tablet computers aregenerally intended for handheld use and ease of portability. Smallerdevices are generally desirable for portability. A touch-sensitivedisplay, also known as a touchscreen display, is particularly useful onhandheld devices, which are small and may have limited space for userinput and output. The information displayed on the display may bemodified depending on the functions and operations being performed.

Improvements in electronic devices with touch-sensitive displays aredesirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a portable electronic device in accordancewith the disclosure.

FIG. 2 is a front view of an electronic device in accordance with thedisclosure.

FIG. 3 illustrates pulses of current signal utilized to drive a driveelectrode during scanning in accordance with the disclosure.

FIG. 4 is a flowchart illustrating an example of a method of detectingtouches on a touch-sensitive display in accordance with the disclosure.

FIG. 5 and FIG. 6 are timelines illustrating detection of touches andreporting the touches in relation to the display update.

DETAILED DESCRIPTION

The following describes an electronic device and a method of controllingthe electronic device. The method includes detecting a touch on atouch-sensitive display, determining a time of a display update of thetouch-sensitive display, and adjusting a length of time of scan of thetouch-sensitive display based on the time of the display update. Forsimplicity and clarity of illustration, reference numerals may berepeated among the figures to indicate corresponding or analogouselements. Numerous details are set forth to provide an understanding ofthe embodiments described herein. The embodiments may be practicedwithout these details. In other instances, well-known methods,procedures, and components have not been described in detail to avoidobscuring the embodiments described. The description is not to beconsidered as limited to the scope of the embodiments described herein.

The disclosure generally relates to an electronic device, which is aportable electronic device in the embodiments described herein. Examplesof portable electronic devices include mobile, or handheld, wirelesscommunication devices such as pagers, cellular phones, cellularsmart-phones, wireless organizers, PDAs, wirelessly enabled notebookcomputers, tablet computers, and so forth. The portable electronicdevice may also be a portable electronic device without wirelesscommunication capabilities, such as a handheld electronic game device,digital photograph album, digital camera, or other device.

A block diagram of an example of a portable electronic device 100 isshown in FIG. 1. The portable electronic device 100 includes multiplecomponents, such as a processor 102 that controls the overall operationof the portable electronic device 100. The processor 102 may be a singleprocessor, a dual-core processor, or multiple processors, although theprocessor 102 is referred to in singular form. The portable electronicdevice 100 presently described optionally includes a communicationsubsystem 104 and a short-range communications 132 module to performvarious communication functions, including data and voicecommunications. Data received by the portable electronic device 100 isdecompressed and decrypted by a decoder 106. The communication subsystem104 receives messages from and sends messages to a wireless network 150.The wireless network 150 may be any type of wireless network, including,but not limited to, data wireless networks, voice wireless networks, andnetworks that support both voice and data communications. A power source142, such as one or more rechargeable batteries or a port to an externalpower supply, powers the portable electronic device 100.

The processor 102 interacts with other components, such as Random AccessMemory (RAM) 108, memory 110, a touch-sensitive display 118, anauxiliary input/output (I/O) subsystem 124, a data port 126, a speaker128, a microphone 130, short-range communications 132, and other devicesubsystems 134. Input via a graphical user interface is provided via thetouch-sensitive display 118. The touch-sensitive display 118 includes adisplay 112 operatively coupled to a display controller 120 and atouch-sensitive overlay 114 operatively coupled to a touch controller116, also referred to as a touch driver. The processor 102 interactswith the display 112 via the display controller 120. The processor 102interacts with the touch-sensitive overlay 114 via the touch controller116. Information, such as text, characters, symbols, images, icons, andother items that may be displayed or rendered on a portable electronicdevice, is displayed on the touch-sensitive display 118 via theprocessor 102. The processor 102 may interact with an accelerometer 136that may be utilized to detect direction of gravitational forces orgravity-induced reaction forces, for example, to determine theorientation of the electronic device 100.

To identify a subscriber for network access, the electronic device 100may optionally use a Subscriber Identity Module or a Removable UserIdentity Module (SIM/RUIM) card 138 for communication with a network,such as the wireless network 150. Alternatively, user identificationinformation may be programmed into memory 110.

The electronic device 100 includes an operating system 146 and softwareprograms or components 148 that are executed by the processor 102 andare typically stored in a persistent, updatable store such as the memory110. Additional applications or programs may be loaded onto theelectronic device 100 through the wireless network 150, the auxiliaryI/O subsystem 124, the data port 126, the short-range communicationssubsystem 132, or any other suitable subsystem 134.

A received signal, such as a text message, an e-mail message, or webpage download, is processed by the communication subsystem 104 and inputto the processor 102. The processor 102 processes the received signalfor output to the display 112 and/or to the auxiliary I/O subsystem 124.A subscriber may generate data items, for example e-mail messages, whichmay be transmitted over the wireless network 150 through thecommunication subsystem 104, for example.

One or more touches, also known as touch contacts or touch events, maybe detected by the touch-sensitive display 118. The processor 102 maydetermine attributes of the touch, including a location of a touch.Touch location data may include an area of contact or a single point ofcontact, such as a point at or near a center of the area of contact. Asignal is received at the touch controller 116 when a touch is detected.A touch may be detected from any suitable input member, such as afinger, thumb, appendage, or other objects, for example, a stylus, pen,or other pointer. The touch controller 116 and/or the processor 102 maydetect a touch by any suitable input member on the touch-sensitivedisplay 118. Multiple simultaneous touches may be detected.

One or more gestures may also be detected by the touch-sensitive display118. A gesture, such as a swipe, also known as a flick, is a particulartype of touch on a touch-sensitive display 118 and may begin at anorigin point and continue to an end point. A gesture may be identifiedby attributes of the gesture, including the origin point, the end point,the distance travelled, the duration, the velocity, and the direction,for example. A gesture may be long or short in distance and/or duration.Two points of the gesture may be utilized to determine a direction ofthe gesture. A gesture may also include a hover. A hover may be a touchat a location that is generally unchanged over a period of time or isassociated with the same selection item for a period of time.

An optional force sensor 122 or force sensors may be disposed in anysuitable location, for example, between the touch-sensitive display 118and a back of the electronic device 100 to detect a force imparted by atouch on the touch-sensitive display 118. The force sensor 122 may be aforce-sensitive resistor, strain gauge, piezoelectric or piezoresistivedevice, pressure sensor, or other suitable device. Force as utilizedthroughout the specification refers to force measurements, estimates,and/or calculations, such as pressure, deformation, stress, strain,force density, force-area relationships, thrust, torque, and othereffects that include force or related quantities.

Force information related to a detected touch may be utilized to selectinformation, such as information associated with a location of a touch.For example, a touch that does not meet a force threshold may highlighta selection option, whereas a touch that meets a force threshold mayselect or input that selection option. Selection options include, forexample, displayed or virtual keys of a keyboard; selection boxes orwindows, e.g., “cancel,” “delete,” or “unlock”; function buttons, suchas play or stop on a music player; and so forth. Different magnitudes offorce may be associated with different functions or input. For example,a lesser force may result in panning, and a higher force may result inzooming.

A front view of an example of the electronic device 100 is shown in FIG.2. The electronic device 100 includes the touch-sensitive display 118.The touch-sensitive display 118 may be a capacitive touch-sensitivedisplay that includes capacitive touch sensors. The touch sensorsinclude, for example, drive electrodes, also referred to as scanningelectrodes, and sense electrodes. The electrodes 202 and the electrodes204 may comprise any suitable material, such as indium tin oxide (ITO).The electrodes 202 and the electrodes 204 are not visible when viewingthe electronic device 100 but are illustrated in FIG. 2 for the purposeof the present description. In the example illustrated in FIG. 2, thevertical electrodes 202 may be the drive electrodes and the horizontalelectrodes 204 may be the sense electrodes. Alternatively, thehorizontal electrodes 204 may be the drive electrodes and the verticalelectrodes 202 may be the sense electrodes.

In this example, the drive electrodes 202 and the sense electrodes 204are coupled to the touch controller 116, for example, via a flexconnector. The drive electrodes 202 are driven by the touch controller116 such that pulses of signal are carried by the drive electrodes 202.The signal may be, for example, current or applied voltage. The senseelectrodes 204 are utilized to detect changes in the signal at the nodes206, which are the locations at which the sense electrodes 204 crossover the drive electrodes 202. To determine a touch location, thetouch-sensitive display 118 is scanned by driving the drive electrodes202 while signals from a sense electrode 204 are received at the touchcontroller 116. Each scan of the touch-sensitive display 118 includesmultiple frames. In each frame, a drive electrode 202 is drivenutilizing multiple pulses, while receiving signals from a senseelectrode 204. Each drive electrode 204 may be driven in multiple frameswhile sensing utilizing each of the sense electrodes 204.

An example of multiple pulses 202 of signal utilized to drive a driveelectrode 202 in one frame of a scan is illustrated in FIG. 3. In theexample of FIG. 3, current pulses are illustrated, and a drive electrode202 is driven utilizing 8 square wave pulses. Alternatively, the pulsesmay be grouped. For example, a drive electrode may be driven utilizingtwo groups, each comprising four pulses. The groups are separated by aperiod of time that may be greater than the period of time between thepulses that comprise a group.

A flowchart illustrating an example of a method of detecting touches onthe touch-sensitive display 118 is shown in FIG. 4. The method may becarried out by software executed, for example, by the touch controller116. Coding of software for carrying out such a method is within thescope of a person of ordinary skill in the art given the presentdescription. The method may contain additional or fewer processes thanshown and/or described, and may be performed in a different order.Computer-readable code executable by at least one processor of theportable electronic device to perform the method may be stored in acomputer-readable medium, such as a non-transitory computer-readablemedium.

When a touch is detected 402, the next display update time is determined404, and the length of time of a scan, or scan time, is adjusted 406based on the display update time such that the touch data is reported bythe touch controller 116 to the processor 102 in time to update thedisplay 112 based on the touch data.

An example of a timeline illustrating detection of a touch and reportingthe touch by adjusting the scan time based on the display update time isillustrated in FIG. 5.

In the example of FIG. 5, a touch is detected at time T504. The touch isdetected during a scan of the touch-sensitive display 118 and prior tocompletion of the scan. The signals received from the sense electrodes204 are utilized to detect a touch during the scan, rather than awaitingcompletion of the scan to detect a touch. For example, driving may becompleted for 3 of 12 of the drive electrodes 202, but not completed forthe remaining 9 of 12 of the drive electrodes 202. The touch may bedetected at the touch controller 116, based on the signals received fromthe sense electrodes 204 during the frames in which the first 3 driveelectrodes 202 are driven.

The touch controller 116 is operably coupled to the display controller120, and the touch controller 116 receives a signal, referred to as theVertical Synchronization or Vsync signal, from the display controller120. The Vsync signal is sent from the display controller 120 to thetouch controller 116 each time the display 112 is updated to update thedisplayed information. The display 112 is updated at regular intervalsof time and the Vsync signal is received by the touch controller 116 atregular intervals in time. The regular interval is determined by thetouch controller 116 and the touch controller 116 determines the time ofthe next display update. In the example of FIG. 5, the display isupdated at time T502, prior to detecting the touch at time T504. Basedon the regular interval, or display update rate, the time of the nextdisplay update is determined to be time T508.

To report the touch data to the processor 102 in time to utilize thetouch data in the next display update at time T508, the touch controller116 adjusts the scan time to report the touch data to the processor 102at time T506, prior to the display update at time T508. The touchcontroller 116 determines the time between time T504 and time T508. Thetouch controller 116 also determines the number of frames remaining inthe scan and determines the length of time remaining for each frame inorder to complete the scan by time T506. Based on the calculated frametime and the length of time for each pulse utilized to drive the driveelectrodes 202 during scanning, the number of pulses utilized to driveeach drive electrode 202 in each frame is determined. The number ofpulses in each frame is decreased to decrease the time of the frame tothe calculated frame time. The number of pulses is decreased to completethe scan in the time remaining until time T506. For example, the numberof pulses may be decreased from 8 pulses, as illustrated in FIG. 3, to 4pulses.

Optionally, the touch data may be reported to the processor 102 alongwith a confidence bit. Based on the confidence bit, the processor 102determines whether or not to utilize the data when updating the display112. For example, the touch controller 116 may determine a confidencebit based on the number of pulses per electrode. In this example, theconfidence bit may be 75% when 6 pulses are sent rather than 8. Theprocessor 102 may determine whether or not to use the data based on theconfidence bit received from the touch controller 116 application orfunction performed. For example, when scrolling, the data may beutilized when a low confidence bit is reported to the processor 102because small inaccuracies may have little effect on the functionperformed. When drawing on the touch-sensitive display 118, however, theaccuracy of the data may be more important, and the processor may notutilize data when a low confidence bit is reported. The confidence bitmay be reported to the host via a register in the interface. Each bit ofthe register may correspond to a confidence level, e.g., 10%, 25%, andso forth.

The scan rate may be adjusted by adjusting the number of pulses suchthat a subsequent scan is completed, and the touch data is reported tothe controller 102 at time T510 prior to the next display update at timeT512.

As described above, the pulses may be grouped. In the example in whichpulses are grouped, the number of pulses in each group may be reduced.Alternatively, or in addition to reducing the number of pulses in eachgroup, the number of groups may be reduced.

Another example of a timeline illustrating detection of a touch andreporting the touch by adjusting the scan rate based on the displayupdate time is illustrated in FIG. 6.

In the example of FIG. 6, a touch is detected and the touch data isreported by the touch controller 116 to the processor 102 at time T604,after the display is updated at time T602. In the example of FIG. 6, thetouch is detected when the full scan of the touch-sensitive display 118is complete.

The display 112 is updated again at time T606. The time between thedisplay update at time T606 and time T608 is determined. Time T608 isthe time by which the touch data is reported to utilize the touch datawhen the display 112 is updated at time T610. The adjusted rate ofscanning may be maintained during the touch to continue reporting touchdata prior to updating the display 112.

Optionally, the touch data may be reported to the processor 102 alongwith a confidence bit. Based on the confidence bit, the processor 102determines whether or not to utilize the data when updating the display112.

When pulses are grouped, the number of pulses in each group may bereduced. Alternatively, or in addition to reducing the number of pulsesin each group, the number of groups may be reduced.

By reducing the number of pulses during touch detection, the timeutilized to scan the touch-sensitive display 118 is decreased. Thenumber of pulses utilized in each frame of a scan is determined based onthe time remaining until the next display update such that the touchdata from the scan is reported to the processor 102 in time to utilizethe touch data when updating the display 112. By adjusting the scan timeto report the touch data prior to updating the display, the delay, alsoreferred to as latency, between a touch or touch movement and displayinginformation relating to the touch or touch movement is reduced. Forexample, when drawing a line on the touch-sensitive display 118, latencycauses a delay between the touch and displaying the line such that thedisplayed line may lag behind the touch. By adjusting the scan ratebased on the display update, the lag is reduced.

A method includes detecting a touch on a touch-sensitive display,determining a time of a display update of the touch-sensitive display,and adjusting a length of time of a scan of the touch-sensitive displaybased on the time of the display update. An electronic device includes atouch sensitive display at at least one controller coupled to thetouch-sensitive display and configured to detect a touch on thetouch-sensitive display, determine a time of a display update of thetouch-sensitive display, and adjust a length of time of a scan of thetouch-sensitive display based on the time of the display update.

The present disclosure may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the present disclosure is, therefore,indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A method comprising: beginning a scan of atouch-sensitive display, the scan including a plurality of frames inwhich drive electrodes are driven while signals are received from senseelectrodes such that a respective drive electrode is driven in eachframe while signals are received from the sense electrodes; in responseto detecting a touch during the scan of the touch-sensitive display andprior to completion of the scan: determining a length of time until anext display update; and decreasing a time of remaining frames of thescan to complete the scan and report the scan prior to a time of a nextdisplay update of the touch-sensitive display, wherein each first frameof the scan completed prior to detecting the touch is completed in afirst length of time and each second frame of the scan completed afterdetecting the touch is completed in a second length of time that is lessthan the first length of time.
 2. The method according to claim 1,comprising utilizing a scan rate for a subsequent scan such that thesubsequent scan is completed and touch data from the subsequent scan isreported prior to a time of a subsequent display update immediatelyfollowing the next display update.
 3. The method according to claim 1,wherein decreasing the time of remaining frames of the scan comprisesreducing a number of pulses applied to the drive electrodes that aredriven in the remaining frames of the scan such that drive electrodesdriven prior to detecting the touch are driven by applying a firstnumber of pulses and the drive electrodes that are driven afterdetecting the touch are driven by a second number of pulses that is lessthan the first number of pulses.
 4. The method according to claim 1,wherein determining the length of time until the next display updatecomprises determining a time based on a Vertical Synchronization signalfrom the touch-sensitive display.
 5. The method according to claim 1,comprising reporting touch data for the scan and a confidence bit to aprocessor.
 6. The method according to claim 5, wherein the confidencebit is determined based on the number of pulses applied to theelectrodes after detecting the touch.
 7. The method according to claim6, comprising determining whether or not to utilize the touch data basedon the confidence bit and based on the function performed utilizing thetouch data.
 8. A non-transitory computer-readable medium havingcomputer-readable code executable by at least one processor of aportable electronic device to: begin a scan of a touch-sensitivedisplay, the scan including a plurality of frames in which driveelectrodes are driven while signals are received from sense electrodessuch that a respective drive electrode is driven in each frame whilesignals are received from the sense electrodes; in response to detectinga touch during the scan of the touch-sensitive display and prior tocompletion of the scan: determine a length of time until a next displayupdate; and decrease a time of remaining frames of the scan to completethe scan and report the scan prior to a time of a next display update ofthe touch-sensitive display, wherein each first frame of the scancompleted prior to detecting the touch is completed in a first length oftime and each second frame of the scan completed after detecting thetouch is completed in a second length of time that is less than thefirst length of time.
 9. An electronic device comprising: atouch-sensitive display; a controller coupled to the touch-sensitivedisplay and configured to: begin a scan of a touch-sensitive display,the scan including a plurality of frames in which drive electrodes aredriven while signals are received from sense electrodes such that arespective drive electrode is driven in each frame while signals arereceived from the sense electrodes; in response to detecting a touchduring the scan of the touch-sensitive display and prior to completionof the scan: determine a length of time until a next display update; anddecrease a time of remaining frames of the scan to complete the scan andreport the scan prior to a time of a next display update of thetouch-sensitive display, wherein each first frame of the scan completedprior to detecting the touch is completed in a first length of time andeach second frame of the scan completed after detecting the touch iscompleted in a second length of time that is less than the first lengthof time.
 10. The electronic device according to claim 9, wherein thecontroller is configured to utilize a scan rate for a subsequent scansuch that the subsequent scan is completed and touch data from thesubsequent scan is reported prior to a time of a subsequent displayupdate immediately following the next display update.
 11. The electronicdevice according to claim 9, wherein the controller is configured todecrease the time of remaining frames of the scan by reducing a numberof pulses applied to the drive electrodes that are driven in theremaining frames of the scan such that the drive electrodes driven priorto detecting the touch are driven by applying a first number of pulsesand the drive electrodes that are driven after detecting the touch aredriven by a second number of pulses that is less than the first numberof pulses.
 12. The electronic device according to claim 9, wherein thecontroller is configured to report touch data for the scan and aconfidence bit to a processor.
 13. The electronic device according toclaim 12, wherein the controller is configured to determine theconfidence bit based on the number of pulses applied to the electrodesafter detecting the touch.
 14. The electronic device according to claim13, comprising a processor coupled to the controller, wherein theprocessor is configured to determine whether or not to utilize the touchdata based on the confidence bit and based on a function performedutilizing the touch data.
 15. The electronic device according to claim9, wherein the controller comprises a touch controller, and a displaycontroller is coupled to the touch controller to send a VerticalSynchronization signal from the display controller to the touchcontroller.
 16. The electronic device according to claim 15, wherein thetouch controller is configured to determine the length of time until thenext display update by determining a time based on the VerticalSynchronization signal from the display controller.